1. Field of the Invention
The present invention relates to an optical coherence tomographic imaging apparatus for capturing a tomographic image of a subject's eye using the interference of light, and relates to a method of controlling the same.
2. Description of the Related Art
Presently, optical coherence tomographic imaging apparatuses based on optical coherence tomography (OCT) using the interference of light of a plurality of wavelengths are known and used to obtain, for example, visceral information through an endoscope or retinal information through an ophthalmic apparatus. The field of application of the optical coherence tomographic imaging apparatuses to a human body is increasingly broadened. The optical coherence tomographic imaging apparatuses applied to the eye are becoming indispensable as ophthalmic instruments for clinics specializing in retina.
Such an optical coherence tomographic imaging apparatus is an apparatus capable of irradiating a sample with measurement light, which is low-coherenct light, and measuring light backscattered from the sample, using an interference system. The apparatus irradiates a point on the sample with the measurement light, and thereby can obtain image information of the sample in the depth direction at the point. Further, the apparatus makes measurements while scanning the sample with the measurement light, and thereby can also obtain a tomographic image of the sample. When applied to the fundus, the apparatus scans the fundus of a subject's eye with the measurement light, and thereby can capture a tomographic image of the fundus of the subject's eye at high resolution. Thus, the apparatus is widely used for the ophthalmic diagnosis of retina.
Generally, an optical coherence tomographic imaging apparatus uses a capturing method for repeatedly scanning the fundus to be measured in a horizontal direction or a vertical direction, thereby obtaining a plurality of tomographic images. The apparatus scans the same location on the fundus a plurality of times to acquire a plurality of fundus tomographic images of the same part. Then, the apparatus performs an averaging process on the plurality of fundus tomographic images, and thereby can obtain a single high-quality fundus tomographic image. Further, the apparatus performs scanning a plurality of times while moving the scanning position in a parallel manner, and thereby can also obtain a three-dimensional image of the fundus. If, however, the apparatus performs scanning a plurality of times as described above, it takes a certain time period to complete all the capturing. Thus, the eye may move during the image capturing.
To solve this problem, the Japanese Patent Application Laid-Open No. 2008-29467 discusses an ophthalmic imaging apparatus having a tracking function for sequentially capturing front images of a subject's eye, detecting the movement of the subject's eye using the plurality of obtained front images, and correcting a scanning position according to the detected movement of the subject's eye.